The Stone Walls of Nihonmatsu Castle 二本松城の石垣

The stone walls of the honmaru (main compound) were originally built in the early seventeenth century. On the east side, only the lower halves of the original walls remained, buried in the earth until they were rediscovered in 1990. The western walls have been visible throughout the castle’s history, but were rebuilt using contemporary techniques sometime after the castle fell in 1868. As a result, a project was launched in 1993 to rebuild all of the honmaru stone walls using traditional techniques. The work was completed in 1995.

The Two-Level Wall

The oldest stone wall in the castle is just north of the honmaru, below the tenshudai (keep foundation). It has never fallen or been rebuilt, and remains exactly as it was in the sixteenth century.

The wall is around 7.5 meters high, divided into a distinct lower and upper half. It was built around 1590 using the nozurazumi technique employed for the walls of the massive Azuchi Castle near the shore of Lake Biwa a decade earlier, sparking a revolution in Japanese castle design.

The Great Wall

Another of the oldest and largest surviving stone walls stands just south of the honmaru. This wall is 13 meters high and 21 meters long at its base. It was built in the late sixteenth century as part of Gamo Ujisato’s project to modernize the castle, reinforcing its earthen construction with stone walls made using construction techniques not available to the original builders.

Minowa Gate

Minowa Gate was built by Niwa Mitsushige as part of his initial civil construction program after taking control of the castle in 1643. It was destroyed when the castle burned in 1868, but rebuilt in 1982. As the main gate of the castle, it was meant to impress.

Otemon Gate

The former site of the castle’s Otemon Gate is outside Kasumigajo Park to the south. This gate stood between the castle and the Oshu Kaido highway, adding an extra degree of protection. It was long desired by the Niwa family, but the Tokugawa shogunate was reluctant to grant permission for more fortifications.

In the early nineteenth century, an ingenious advisor named Niwa Takaaki came up with a workaround. He first asked permission to build a wall instead of a gate, then requested leave to add a building on top of the wall. This ruse was successful, and Otemon Gate was completed in 1832. A section of the gate’s stone wall still stands today. It is an example of kikkozumi-kuzushi or “turtle shell” masonry, so called because rocks were dressed in roughly hexagonal shapes that fit together snugly in a turtle-shell pattern.